Capillary electrometer for relay purposes.



UNITED STATES PATENT OFFICE.

ALBERT C. CREHORE, OF TARRYTOWVN, NEW YORK, AND GEORGE O. SQUIER,

OI \VASHINGTON, DISTRICT OF COLUMBIA, ASSIGNORS TO THE CREI'IORE- SQUIER INTELLIGENCE TRANSMISSION COMPANY, OF CLEVELAND, OHIO.

CAPI LLARY ELECTROM ETER FOR RELAY PU RPOSES.

SPECIFICATION forming part of Letters Patent N 0. 669,149, dated, March 5, 1901.

Application filed October 20,1899. berial No. 734,177. (No model.)

To (1% whom it may concern: 1, in section and diagrammatically, the cap- Be it known that we, ALBERT C. CREHORE, illary electrometer and the manner in which a resident of Tarrytown, Westchester county, it may be made to relay a circuit to a local NewYork, and GEORGE O. SQUIER,R resident circuit. Fig. 2 shows a modified construcof \Vashington, Dist-rictof Columbia, citizens tion. 55

of the United States, haveinvented a certain In said drawings, 1 refers to the mercurynew and useful Capillary Electrometer for tube of the electrometer, and 2 to the vessel Relay Purposes, of which the following is a containing mercury in its bottom and dilute specification. sulfuric acid above it. This vessel is prefer- This invention relates to the use of a capably open to the air, as shown by the passage 60 ill-ary electrometer for relay purposes, said 3 in its cork. electrometer being substantially such as that 4 refers to the mercury in the tube, and 5 disclosed byLippmann. TheLippmann electo the meniscus between the mercury and trometer consists of a glass tube drawn down the acid. to capillary size at its lower end and filled 6 7 refer to the terminals of the main cir- 65 with mercury. Said lower end was then imcuit. mcrsed in a vessel containing dilute sulfuric The tube 1 is sealed, and the space above acid and a layer of mercury, the end of the the mercury is preferably filled with some tube being at some distance above the merliquid of slight compressibility, such as oil. cury in the vessel. Terminals of an electric In the oil is locateda receptacle, as 8, (shown 70 circuit were connected to the mercury in the in vertical transverse section,) one or both tube andin the vessel, respectively. Thesulsides of which are formed of metallic diafuric acid arose in the tube by capillary atphragms. These are insulated from each traction and raised the mercury therein to a other and form terminals of the local circuit certain point. Then as the electric circuit 9, and between these diaphragms a suitable 75 was completed any variation in potential at variable resistance is placedsuch, for inthe terminals of the circuit would cause the stance, as carbon granules.

meniscus formed between the surfaces of the Any variation in the elevation of the mermercury and acid in the tube to move up and cury in tube 1 will cause the diaphragms of down,theextentof movementof the meniscus receptacle 8 to be pressed inward, thereby 8o measuring said variation. Upon this phedecreasing the resistance through the granunomenon the presentinventionis based. The lar carbon, and vice versa. Therefore by circuit whose fluctuations or variations in poplacing in the local circuit 9 any suitable detential are to be utilized is connected to the vice responsive to this variable resistance terminals of the capillary electrometer. Said the variations in the main circuit may be 85 electrometer may then be made to operate shown. For example, a Wheatstone-bridge upon another or local circuit by utilizing the arrangement may be employed, as indicated, movement of the mercury in the tube. This in one leg of which the variable resistance 8 movement may be made use of by means of is placed, the other legs each having a fixed any of the various devices for multiplying resistance, and in the bridge is placed the 90 motion and the resultant applied to the openoperating-coil 10, of any suitable indicator ing and closing of an electric circuit or to the or recordersuch, for instance, as a siphonvariation of resistance in such circuit, or said recorder.

movement may be made to act more directly It is clear from the above description that upon a resistance in such circuit, as will be a change in potential in the circuit 6 7 will 5 hereinafter described, as the most practical cause a movement of the meniscus 5, which means yet conceived for the utilization of all means a change in the height of the mercury ol' the movements of the mercury column even in tube 1 and a variation in the pressure on to the slightest. the diaphragm of the receptacle 8-hence a The accompanyingdrawingsshowinFigure change in the resistance in said receptacle and an unbalancing of the bridge, and consequently a flow of current over the coil 10, whereby an indication or record is produced.

The meniscus is very sensitive and rapid in its movements, and therefore the apparatus is Well adapted for use as a receiver for submarine cables. Though especially applicable to the above use, it is clear that it is capable of a wide range, since it responds quickly to changes of current, the deflection of the meniscus is proportional to difference of potential, it takes no current, it is dead heat, and it responds to exceedingly small voltages.

No attempt has been made to illustrate a working apparatus, but simply to give a clear idea of the adaptation of the capillary electrometer to practical uses. Obviously the movements of the meniscus may be trausmitted in a purely mechanical manner, as by a series of levers, to that on which the changes in circuit 6 '7 are to be impressed, or the movements of the mercury in tube 1 may be made to act upon a variable resistance in many ways other than that shown. The transmission of the movements of the meniscus by lever construction is graphicallyillustrated in Fig. 2, wherein the piston 11 is placed upon the mercury in tube 1', and upon this rests a lever12, fulcrumed at 13 and resting at its opposite end upon a post 14, which is supported by the upper diaphragm of the variable resistance 8 in the circuit 9. Obviously any movement of the piston will be transferred to and multiplied upon this variable resistance. All these variations and many others may be made in adapting the capillary electrometer to practical use without departing from the invention residing in the adaptation thereof to the purposes of a relay.

We claim as our invention- 1. The combination with a capillary electrometer, substantially such as described, of

an electric circuit controlled by the movement of the fluids separated by the meniscus in said electrometer.

2. The combination with a capillary electrometer, substantially such as described, of a liquid body or column affected by the movements of the liquids separated by the meniscus in said electrometer and means actuated by said column of liquid for controlling an electric circuit.

3. The combination with a tube containing conducting fluids between which a meniscus is formed and the position of which meniscus is varied by the fluctuation ofan electric current passed through the liquids across the meniscus, of an electric-circuit-controlling apparatus actuated in response to the movements of the fluid above the meniscus.

4. The combination with the capillary electrometer, substantially such as described, of a closed space or chamber above the mercury in the capillary tube of the electrometer filled with a non-compressil'ile fluid, and a currentvaryiug device located in said fluid and operated by the rise and fall of the mercury.

5. The combination with a capillary electrometer substantially as described, of a closed space or chamber above the mercury in the capillary tu be of the elect-rometer filled with a non-compressible fluid, a receptacle located in said chamber and having flexible walls, a variable resistance within said receptacle, an electric circuit containing said resistance, and an indicator in said circuit, for the purpose set forth.

Signed at New York city, in the county of New York and State of New York, this 12th day of June, 1900.

ALBERT C. CREHORE. GEORGE O. SQUIER.

Witnesses:

DELBERT H. DECKER, ETHEL L. LAWLER. 

